Scribe Post 11/8

Today in class we:

1. Talked about the last page ofthe meiosis notes
2. Worked on the Karyotype lab (pages 19-37 in the UP)

NOTES

• Breakage of a chromosome (this is the breakage of segments of a chromosome NOT the A,T,G,C parts)
• Deletion- A chromosome loses a fragment of itself
• Duplication- Occurs when a fragment from another chromosome is inserted into a homologous chromosome
• Inversion- A fragment breaks off from a chromosome then reattaches itself upside down
• Translocation- Occurs when a fragment reattaches to a nonhomologous chromosome

KARYOTYPE LAB

• We used the cutouts from page 21 in the UP and put them into pairs
• Then we taped them down according to number on the worksheet (page 23, UP)
• We did this for the rest of class
• Pages 26 and 27 are questions about this karyotype (page 23)

HOMEWORK

• Study for the quiz tomorrow!
• Finish UP p. 19-37 (This is where you use your assigned sheet - B,C, or D - to make another karyotype on page 37)
• EC - UP p. 39-40 in the UP
• Read CH 9 p. 142-168

DO NOT DO THE "GOING FURTHER" PART AT THE BOTTOM OF PAGE 27!!! IT IS NOT

HOMEWORK!!!

Next scribe *****Nazia*****

Scribe Post 11/7

Today in class we:

1. Turned in the homework, UP pages 3-4, 9-11, and our spice lab write up


2. Finished the meiosis notes


3. Watched a video on meiosis

In the video, we reveiwed the process of sexual reproduction in cells, and got more into depth with crossovers in chromosomes, exchanging genetic information thus adding diversity to the cell.

IN THE NOTES:

In the notes in class, we began with explaining the 3 resons for variety in species:

1. 
   
   Independent Assortment: the arrangement of the homologous chromosome pairs at metaphase 1 varies and is a matter of chance. Each pair orients itself independently of the other pair. This affects the the resulting gametes=variety. Each human gamete has 8 million possible combinations.


2. 
   
   Random Fertiliazation: 1 egg (8 million possible combinations) with 1 sperm (8 million possible combinations) results in 64 trillion different potential combinations.


3. 
   
   Crossing Over: This is the exchanging of genetic information by homologous chromatids, creating a genetic recombination.

After this, we moved on to explaining possible errors that may occur during meiosis:

1. 
   
   Nondisjunction: This is when the chromosomes fail to seperate during Anaphase I or II. This occurs with autosomes or sex chromosomes, thus leading to a mutation.

Some examples of a mutation or disorder caused by a nondisjunction are:





• Trisonomy 21 (Down Syndrome): This is when a nondisjunction occurs in the 21st chromosome, resulting in three (a trisonomy) of chromosome 21.


• Klinefelter Syndrome- male XXY: This syndrome occurs when the X chromosome fails to seperate and the male is left with two X chromosomes and a Y


• Turner Syndrome- female XO: This syndrome also occurs in the X chromosome, except the female is missing an X chromosome due to a disjunction

2. Breakage of a chromosome:

• Deletion: if a fragment of genetic information is lost, the remaining chromosome has a deletion


• Duplication: If a fragment of a chromosome is inserted into another homologous chromosome, it produces a duplication there.


• Inversion: If a fragment of genetic information is detatch from the chromosome and then retatched in the reverse direction, an inversion has occured


• Translation: If a fragment of genetic information attatches to a nonhomologous chromosome, a translation of genetic information has occured.

Tonights homeworks is:

• Cut out page 21 and put it in a SEPERATE bag from your assigned page (B, C, or D)


• Study for quiz.

Next Scribe: ***Eleni***

Scribe Post 11/4

In class today, we discussed the homework due monday, which is:

• UP 3-7
• Spice Lab
• UP 9-11
• UP 15-16B
• Study Mitosis vs. Meiosis

We also filled a good portion of the meiosis notes. These notes are on the moodle page as usual.


Meiosis is the special type of cell division carried out by organisms for sexual reproduction. It produces 4 genetically different cells that are also haploid.

Here are the stages of meiosis:

Prophase I: Here the cells prepare for division just like in mitosis.

Metaphase I: Here the chromosomes line up in the middle and the spindle forms.

Anaphase I: Here the chromosomes split off to the poles.

Telophase I/ Prophase II: 2 Daughter cells are formed, and cytokinesis occurs.

Metaphase II: Chromosomes line up in the middles of their respective cells.

Anaphase II: The DNA splits off to the poles of each cell.

Telophase II: 4 distinct, genetically different cells are formed.

Thank You